Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines generally comprise a rotor with a rotor hub and a plurality of blades. The rotor is set into rotation under the influence of the wind on the blades. The rotation of the rotor shaft drives the generator rotor either directly (“directly driven”) or through the use of a gearbox. The gearbox (if present), the generator and other systems are usually mounted in a nacelle on top of a wind turbine tower. In order to extract a larger amount of energy from the wind, the blades are ever increasing in size and the towers are made taller to enable the rotor to capture more wind at higher altitudes.
Wind turbine towers both for onshore and offshore applications are usually formed by a number of tubular tower sections, which are fastened together at flanges by a series of bolts.
The tower sections are adapted to house a number of operating components of the wind turbine. Examples of wind turbine operating components that may be housed inside a wind turbine tower are electrical power modules, transformers, frequency converters, switch cabinets, inverters, control units, power cables, ladders, platforms, service lifts, etc.
The designs of wind turbine towers vary considerably, depending on each make and model. The following, however, are typical operating components:                A fixed ladder provided in the tower sections to afford the maintenance personnel a means to ascend and descend the tower to perform job tasks;        A certified fall arrest system installed throughout the length of the ladder to provide continuous fall protection.        
Wind turbines typically have computer control (SCADA) systems and are operated remotely. If a wind turbine faults, it may be reset remotely. If it cannot be remotely reset, maintenance personnel may need to enter the turbine to troubleshoot the fault and correct it. This may involve corrective maintenance and a turbine ascent/descent by the maintenance personnel using the fixed ladders.
Many companies in the wind industry have also installed climb assists on some wind turbines to reduce the physical exertion required to ascend and descend ladders.
Climb assist systems are typically systems that will assist maintenance personnel during the climb. Maintenance personnel will be coupled to their fall protection system while also using the climb assist system. The maintenance personnel's harness may be connected to a cable or rope that goes to the top of the ladder, over a pulley and back down in a continuous loop.
The system pulls the employee upward reducing the weight supported by the body during the climb. This type of climb assist system will typically have a continuous cable that is driven by a motor.
One of the several problems associated with the use of ladders is that the clearance space within the wind turbine towers is narrow, thus creating a potential hazard for personnel ascending and descending inside the tower. Particularly, some of the bolts, or tower flanges or other components protruding into the clearance space within the wind turbine towers could cause bodily harm for maintenance personnel going up and down a ladder.
Use of climb assistance increases the speed at which climbers move up and down the turbine ladder. This means that users approach flanges at a faster rate.
Examples of the present disclosure seek to at least partially reduce one or more of the aforementioned problems. Even though the present disclosure is aimed at wind turbine towers, similar problems may exist in other towers, in particular towers, wherein tower sections are mounted on top of each other and attached to each other at flanges.